纳米碳混合层对土壤水分入渗特性及水分分布影响

Influence of Nano-carbon Composite Layer on Soil Water Infiltration and Water Distribution

通过室内一维垂直土柱试验,利用TDR和张力计分别研究土壤中纳米碳混合层对土壤水分入渗特性、土壤水分分布以及纳米碳混合层对土壤水分特征曲线的影响。结果表明:(1)随着入渗时间的增加,含有纳米碳的土壤在相同入渗时间内累积入渗量减少,湿润锋推进距离明显减小,施加纳米碳具有明显的减渗作用。利用Philip入渗模型拟合入渗数据,吸渗率S随着纳米碳含量的增加而减小,随着纳米碳含量的增加,水分入渗初期的累积入渗量逐渐减小。对湿润锋分层进行线性拟合,在湿润锋进入第2层土壤时,入渗速率有了显著的降低,纳米碳混合层有着明显的阻水效果。(2)随着纳米碳的加入,纳米碳混合层的含水量明显提高,纳米碳混合层下层的土壤含水量相对于空白对照组土壤含水量更低;当纳米碳含量为0.5%时,纳米碳混合层的土壤含水量达到最大值。(3)随着纳米碳的施入,在土壤脱湿状态下,能显著提高土壤的持水能力,运用van Genuchten模型对水分特征曲线进行拟合,公式中的土壤的滞留含水率、饱和含水率及与进气值相关系数较不加纳米碳的土壤明显增加,形状系数n则小于不加纳米碳的土壤。

The effects of nano-carbon on soil water infiltration,soil water characteristic curve and soil water distribution were studied by TDR and tensiometer through one dimensional vertical soil column test.The results showed that：（1）With the increasing of infiltration time,the cumulative infiltration amount of the soil contained nano-carbon decreased in the same infiltration time,and the advancing distance of wetting front decreased obviously,and the application of nano-carbon presented obvious infiltration reduction effect.Using Philip infiltration model to fit infiltration data,the infiltration rate S decreased with the increasing of nano-carbon content,meanwhile with the increasing of nano-carbon content,the cumulative infiltration amount decreased gradually in the early stage of water infiltration.The linear fitting of wetting front in different layers showed that infiltration rate decreased significantly when wetting front entered second layers of soil,and nano-carbon layer had obvious effect of water blocking.（2）Adding nano-carbon,the water content of nano-carbon composite layer increased obviously,and soil water content in the lower layer of the nano-carbon composite layer was lower than that in the blank control group.When the nano-carbon content was 0.5%,the soil water content of the nano-carbon composite layer was the maximum.（3）Adding nano-carbon could significantly improve the water holding capacity of soil when the soil was under dehydration condition;the soil water characteristic curves were fitted using the van Genuchten model,and the soil water retention rate（θr）,saturated water content（θs）and the correlation coefficient（α）of the formula significantly increased compared with the soil without nano-carbon,andthe shape coefficient nwas smaller than that of the soil without nano-carbon.